The present invention is directed to the field of roofing structures and, in particular, to brackets used in roofing structures.
Roofing structures in a sloped build-up structural support construction, include a plurality of elongated vertical support posts fastened to roof substrates such as various components combined to comprise the roof composition, which are supported by steel bar joists or other load bearing material. The vertical posts may be fastened directly to the roof substrate or to a base member fastened to the substrate. Fastened to an upper end of the vertical support members are elongated horizontal support members or purlins. Transverse support frames may be constructed at each end of the roof and have brace members extending between the eave line and the ridge at the desired roof grade. The purlins overlap each other longitudinally and extend horizontally along the length of the roof between the brace members of the transverse support frames. The vertical posts are disposed at laps of the purlins and at other intermediate locations. In positions from the eave line toward the ridge, the purlins are disposed at successively higher elevations from the roof substrate.
The construction of roofing structures requires careful planning and attention to specifications. Brackets are used for fastening the vertical posts to the purlins and brackets may be used for fastening the vertical posts to the roof substrate. Workers place brackets in desired positions and drive fasteners through a bracket and into the vertical posts, the purlins, or the roof substrate.
Installers often do not position the screws in the most effective locations on the brackets during installation. Proper screw location on the brackets is important for providing the roofing structure with appropriate strength. Sometimes installers locate the screws too close together, which weakens the structure. In view of the harsh environment of wind, heat and moisture to which roofing structures are exposed, roofing systems that have reduced strength due to ineffective installation, present problems for manufacturers.
In general, the present invention is directed to roofing brackets or clips used in the fabrication of roofing systems. The roofing bracket includes a plurality of preformed, patterned holes which enable the roofing system to be fabricated effectively and reliably. The brackets are advantageous in that the patterned, preformed holes direct installers to position the fasteners at predetermined locations on the bracket and into the surface to which the bracket is fastened. This provides a reliable, high strength roofing system.
A preferred embodiment of the invention is directed to a roofing structure comprising a plurality of generally vertical members (e.g., posts) fastened to a lower support surface, a plurality of generally horizontal members (e.g., purlins) fastened to the vertical members, and brackets for anchoring the horizontal members to the vertical members. The invention is also directed to the roofing brackets themselves. Each of the brackets comprises a first leg that can be attached to the vertical members and a second leg that extends at an angle from the first leg and can be attached to the horizontal members and/or the support surface. The first leg and the second leg include a plurality of preformed holes having sizes that can receive fasteners. The holes in the first leg are arranged in a pattern of more than one row of holes effective to enable fasteners extending through these holes to be positioned near a generally vertical center line of the vertical members. The roofing system also preferably includes elongated brace members each fastened at a predetermined roof grade to the vertical members at a location below the horizontal support members. Roofing panels are fastened to the horizontal support members.
Referring now to more specific features of the invention, the horizontal members have an upper surface for receiving a roof panel. The pattern in the first leg of the bracket comprises the rows of holes spaced apart from each other by distances sufficient to enable the bracket to be rotated such that the upper surfaces of the horizontal members will be positioned to support the roof panel at a predetermined grade while locating holes of the rows near a generally vertical center line of the vertical members. The pattern preferably comprises two rows, center lines of the holes in each row being aligned with each other.
The holes in the second leg of the bracket may be oriented in a pattern effective for fastening to the support surface. These holes have different sizes for receiving different fasteners. The second leg may further comprise slots. The pattern of holes in the second leg is generally rectangular. Four slots are disposed near each corner of the pattern. First holes are disposed near a long side of the pattern between slots and second holes are disposed near a center of the pattern. The first holes are preferably larger than the second holes. A size of the second holes is effective for receiving self-drilling screws for fastening to steel support members and lag screws for fastening to wood structural members. A size of the first holes is effective for receiving fasteners for fastening to wood and concrete.
The second leg of the bracket may be formed such that a spacing between the slots and a length of the slots are effective to enable fasteners in each of the slots to be fastened near center lines of adjacent bar joist flanges for fastening to different sizes of bar joists. The dimension of the slots in the second leg is preferably about {fraction (1/4xc3x973/4)} inch. The slots are spaced apart from each other by about ⅝ inch in a direction of elongation of the slots.
The roofing system is advantageous in that the plurality of preformed, patterned holes in the brackets enable effective and reliable fabrication. The patterned holes effect this high strength, reliable construction, by controlling the locations of fastener installation. The strength of the roofing system is also increased because the roofing clips can be rotated into a position to achieve a desired roof grade, while permitting holes in the clips to be aligned along a vertical center line of the vertical support members, which is a location of a high strength connection. The roofing clips are also versatile in that they can be used in both the upper and lower locations of the vertical support members, and are engineered to be fastened to most sizes of steel bar joists.
A method of fabricating a roofing structure according to the invention comprises positioning a second leg of a roofing bracket on a lower support surface (e.g., on a surface of a roof substrate). Certain of different sized preformed holes in the second leg are selected to accommodate a fastener that can extend into the support surface. Fasteners are positioned in the selected holes and driven into the support surface. A first leg of the bracket is fastened to a bottom portion of a generally vertical support member. Certain of a plurality of patterned holes in a first leg of another upper bracket are selected to position an upper surface of a generally horizontal member (e.g., purlin) at a desired grade while aligning the selected holes near a vertical center line of the vertical member. Fasteners are positioned in the selected holes of the first leg portion of the upper bracket. In particular, one fastener is positioned in a hole of one of the rows and another fastener is positioned in a hole of the other row, both holes being near the vertical center line of the vertical member. The fasteners are driven into the vertical members. A second leg of the upper bracket is fastened to the horizontal member.
Other embodiments of the invention are contemplated to provide particular features and structural variants of the basic elements. The specific embodiments referred to as well as possible variations, and the various features and advantages of the invention, will become better understood from the accompanying drawings, together in connection with the detailed description that follows.